Define MINGW_W64 and use it instead of _W64

... for detecting MinGW-w64. _W64 is not specific of MinGW-w64, it is
defined for compatibility with MS VC++.

	* nt/inc/ms-w32.h: Define MINGW_W64.

	* admin/CPP-DEFINES: Mention MINGW_W64.

	* nt/addpm.c: Use it.

	* nt/addsection.c: Use it.

	* nt/preprep.c: Use it.

	* src/w32.c: Use MINGW_W64 instead of _W64

	* src/w32term.c: Likewise.

1 files changed, 2 insertions, 1 deletions

diff --git a/admin/CPP-DEFINES b/admin/CPP-DEFINES
index 27d87dcaa2a..e475b422500 100644
--- a/admin/CPP-DEFINES
+++ b/admin/CPP-DEFINES
@@ -19,8 +19,9 @@ __MSDOS__	Ditto.
 __DJGPP_MINOR__ Minor version number of the DJGPP library; used only in msdos.c and dosfns.c.
 DOS_NT          Compiling for either the MS-DOS or native MS-Windows port.
 WINDOWSNT       Compiling the native MS-Windows (W32) port.
-__MINGW32__     Compiling the W32 port with the MinGW port of GCC.
+__MINGW32__     Compiling the W32 port with the MinGW or MinGW-w64 ports of GCC.
 _MSC_VER        Compiling the W32 port with the Microsoft C compiler.
+MINGW_W64       Compiling the W32 port with the MinGW-w64 port of GCC.
 DARWIN_OS       Compiling on Mac OS X or pure Darwin (and using s/darwin.h).
 SOLARIS2
 USG